The objective of the proposed research is to establish an animal model system to study the virological parameters of the interaction of insecticide carriers with a virus-infected host. The viruses that will be studied in the mouse include encephalomyocarditis (EMC) virus, influenza types A and B, and a mouse-brain-adapted strain of measles virus. Mice will be pretreated with insecticide carrier and then infected with virus. They will then be observed for a prescribed period of time using a reduction in the mean day of death, or elicitation of a specific disease, as an index of an effect of the insecticide carrier on the virus-infected host. Additional studies will be aimed at elucidating the mechanism(s) responsible for the effects observed. These studies include an assessment of the degree of virus dissemination in tissues of the host using conventional quantitative assays for infectious virus and the indirect method of immunofluorescence for viral antigens, as well as conventional histopathological and specific staining procedures to determine the pathological character of the effect. In addition, studies will be carried out to determine the interferon response of the host and the effect of interferon treatment on the evolution of the effect precipitated by viral infection and insult with insecticide carrier. Consideration will be given to evaluating the effect of insecticide carriers on the mouse-virus systems proposed to provide an animal model simulating Reye's syndrome in man.